This is a K23 application for Dr. Vanessa H. Bal, an Assistant Professor in Psychiatry at the University of California San Francisco. Dr. Bal is establishing herself as a clinician-scientist who conducts interdisciplinary, patient-oriented research aimed at advancing understanding of the biological bases of Autism Spectrum Disorder (ASD) symptoms. This K23 will provide Dr. Bal with essential support to accomplish the following goals: 1) develop expertise in the theoretical basis of affective science; 2) gain methodological proficiency (collection and analysis of psychophysiological and facial behavior data) to conduct future emotion studies in children with ASD across the range of ability (e.g., minimally verbal); 3) gain familiarity with the neural systems mediating emotion processes; 4) obtain the knowledge necessary to use laboratory-based findings to understand mechanisms underlying clinical measures of socioemotional impairments; 5) learn to translate clinical phenotypes to animal model and treatment development studies; 6) acquire knowledge needed to conduct longitudinal research with neurodevelopmental populations; and 7) develop an independent interdisciplinary research career. To achieve these goals, Dr. Bal has assembled a multidisciplinary mentoring team including a primary mentor: Dr. Howard Rosen (a neurologist with expertise in psychophysiology and the organization of emotional systems in the brain); four co-mentors: Drs. Virginia Sturm (a neuropsychologist with expertise in laboratory assessment of emotion and social behavior in patients), Stephen Hinshaw (a psychologist with expertise in developmental psychopathology and longitudinal studies of neurodevelopmental disorders), and Matthew State (a psychiatrist and geneticist with expertise in interdisciplinary ASD research); and a statistical advisor, Dr. Kevin Delucchi (a biostatistician with expertise in psychiatric research). The proposed project explores the relationship between emotional processes (reactivity and regulation) and socioemotional dysfunction in ASD. Dr. Bal will use laboratory-based paradigms to measure physiological (cardiac, respiratory, electrodermal) and behavioral (facial muscles) emotional reactivity and regulation in child- ren with ASD and typically development (Aims 1 & 2). She will then integrate laboratory findings with clinical measures of socioemotional functioning and ASD symptoms to determine the real-world impact of emotional impairments (Aim 3). The goal of Dr. Bal's research is to identify mechanisms underlying socioemotional impairments that can be used to delineate associations between genetic risk factors and clinical outcomes. This project is innovative because it explores the potential role of emotion processing in ASD symptoms, using well-established, translational methods from affective science that have clarified mechanisms underlying clinical impairments in other patient groups. Results will significantly contribute to our understanding of the biological basis of ASD symptoms. Dr. Bal's K23 training will prepare her to conduct cutting-edge studies of aberrant socioemotional development across the lifespan that will inform clinical and basic ASD research.